U.S. patent number 8,997,719 [Application Number 12/580,387] was granted by the patent office on 2015-04-07 for fuel vapor processing apparatus.
This patent grant is currently assigned to Aisan Kogyo Kabushiki Kaisha. The grantee listed for this patent is Takanori Akiyama, Ryuji Kosugi. Invention is credited to Takanori Akiyama, Ryuji Kosugi.
United States Patent |
8,997,719 |
Kosugi , et al. |
April 7, 2015 |
Fuel vapor processing apparatus
Abstract
The present invention includes a fuel vapor processing apparatus
including a communication passage connecting between a first space
and a second space each containing an adsorption material capable
of adsorbing fuel vapor. The communication passage includes a
dissipation delaying space capable of delaying dissipation or
transmission of the fuel vapor between the first and second spaces.
The communication passage further includes throttles positioned to
oppose to each other across the dissipation delaying space.
Inventors: |
Kosugi; Ryuji (Obu,
JP), Akiyama; Takanori (Obu, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kosugi; Ryuji
Akiyama; Takanori |
Obu
Obu |
N/A
N/A |
JP
JP |
|
|
Assignee: |
Aisan Kogyo Kabushiki Kaisha
(Obu-shi, Aichi-ken, JP)
|
Family
ID: |
42107637 |
Appl.
No.: |
12/580,387 |
Filed: |
October 16, 2009 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100095938 A1 |
Apr 22, 2010 |
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Foreign Application Priority Data
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Oct 21, 2008 [JP] |
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2008-270914 |
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Current U.S.
Class: |
123/519; 96/131;
96/133 |
Current CPC
Class: |
F02M
33/02 (20130101); B60K 15/03504 (20130101); Y02T
10/12 (20130101); F02M 33/025 (20130101); B60K
2015/03514 (20130101) |
Current International
Class: |
F02M
33/04 (20060101); B01D 53/02 (20060101) |
Field of
Search: |
;123/519,516,518,520,698
;96/133 ;137/587-589 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10037812 |
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Feb 1998 |
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JO |
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07-151021 |
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Jun 1995 |
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JP |
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2001343845 |
|
Nov 2001 |
|
JP |
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2002-235610 |
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Aug 2002 |
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JP |
|
2005023835 |
|
Jan 2005 |
|
JP |
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2005-195007 |
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Jul 2005 |
|
JP |
|
2008-144699 |
|
Jun 2008 |
|
JP |
|
Primary Examiner: Gimie; Mahmoud
Assistant Examiner: Hamaoui; David
Attorney, Agent or Firm: Ladas & Parry LLP
Claims
This invention claims:
1. A fuel vapor processing apparatus comprising: a first canister
including a first case body that defines therein a first adsorption
chamber, a second adsorption chamber and a dissipation delaying
space; and a second canister including a second case body that
defines therein an atmospheric-side adsorption chamber; wherein:
each of the first adsorption chamber and the second adsorption
chamber of the first canister contains a tank-side adsorption
material; the atmospheric-side adsorption chamber of the second
canister communicates with the dissipation delaying space and
contains an atmospheric-side adsorption material; the first
adsorption chamber of the first canister communicates with a space
within a fuel tank and is configured such that that fuel vapor
dissipating from the space within the fuel tank is adsorbed by the
tank-side adsorption material of the first adsorption chamber as
the fuel vapor flows in a first direction within the first
adsorption chamber; the second adsorption chamber is disposed on a
downstream side of the first adsorption chamber and is configured
such that the fuel vapor is adsorbed by the tank-side adsorption
material of the second adsorption chamber as the fuel vapor flows
in a second direction within the second adsorption chamber; the
second direction is opposite to the first direction; the
dissipation delaying space is disposed on a downstream side of the
second adsorption chamber and containing no adsorption material, so
that the dissipation delaying space is capable of delaying
dissipation of fuel vapor flowing from the second adsorption
chamber; the fuel vapor dissipated within the dissipation delaying
space flows in the second direction and further flows into the
atmospheric-side adsorption chamber of the second canister so as to
be adsorbed by the atmospheric-side adsorption material; the first
canister further includes a first throttle and a second throttle
respectively disposed at a first end and a second end of the
dissipation delaying space, the first end and the second end being
opposite to each other with respect to the second direction; the
first throttle is a plurality of through holes formed in a
partition plate disposed at the first end of the dissipation
delaying space; the second throttle is a connection port provided
at the first case body, so that the fuel vapor flows from the
dissipation delaying space of the first canister to the
atmospheric-side adsorption chamber of the second canister via the
connection port; the dissipation delaying space has a first length
along the second direction; the second adsorption chamber has a
second length along the second direction; and the first length is
longer than the second length and is longer than half a length of
the first adsorption chamber along the first direction.
2. The fuel vapor processing apparatus as in claim 1, wherein the
plurality of through holes have a rectangular shape.
3. The fuel vapor processing apparatus as in claim 2, wherein at
least one side of the rectangular shape has an arc shape.
4. The fuel vapor processing apparatus as in claim 1, wherein the
partition plate includes a plurality of projections that hold a
filter.
5. The fuel vapor processing apparatus as in claim 1, wherein the
first canister further includes a partition wall disposed within
the first case body and extending substantially in parallel to the
first and second directions, wherein an inner space of the first
case body is separated into a first side space and a second side
space by the partition wall, the first adsorption chamber is
positioned in the first side space, and the second adsorption
chamber and the dissipation delaying space are positioned in the
second side space.
6. The fuel vapor processing apparatus as in claim 1, wherein the
dissipation delaying space has a first cross sectional area within
a first plane along the second direction, the second adsorption
chamber has a second cross sectional area within the first plane
along the second direction, the first cross sectional area is
larger than the second cross sectional area.
7. The fuel vapor processing apparatus as in claim 6, wherein the
first adsorption chamber has a third cross sectional area within a
second plane along the first direction, the second plane is the
same plane as the first plane, and the third cross sectional area
is larger than the first cross sectional area of the dissipation
delaying space.
Description
This application claims priority to Japanese patent application
serial number 2008-270914, the contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel vapor processing apparatus
for processing fuel vapor that may be produced within a fuel
tank.
2. Description of the Related Art
A known fuel vapor processing apparatus includes a tank-side
adsorption material contained in a first space communicating with a
space within a fuel tank, and an atmosphere-side adsorption
material contained in a second space having one end communicating
with the first space via a communication passage and having the
other end open into the atmosphere. Therefore, the tank-side
adsorption material within the first space can adsorb fuel vapor
dissipated from the space within the fuel tank. The atmosphere-side
adsorption material within the second space can adsorb a part of
the fuel vapor that may be leaked from the first space.
This type of fuel vapor processing apparatus is disclosed, for
example, in Japanese Laid-Open Patent Publication No. 10-37812. As
shown in FIG. 9, a fuel vapor processing apparatus disclosed in
this publication includes a first canister 101 and a second
canister 102. The first canister 101 has a first space 101s defined
therein and containing activated carbon C. The second canister 102
has a second space 102s defined therein and containing honeycomb
activated carbon H. The first canister 101 includes a tank port
101t communicating with a space defined within a fuel tank (not
shown), so that fuel vapor dissipated from the space within the
fuel tank can be adsorbed within the first canister 101. The second
canister 102 can adsorb a part of the fuel vapor leaked from the
first canister 101 and is connected to the first canister 101 via a
communication pipe 103. The second canister 102 is formed with an
atmospheric port 102e at an end surface on the side opposite to the
communication pipe 103.
Therefore, for example, during filling of fuel into the fuel tank,
air within the fuel tank may be discharged to the atmosphere from
the atmospheric port 102e via the first canister 101, the
communication pipe 103 and the second canister 102.
According to the fuel vapor processing apparatus of the above
publication, a part of the fuel vapor leaked from the first
canister 101 may quickly reach the second canister 102, because the
first canister 101 and the second canister 102 are connected to
each other by the communication pipe 103 that has a relatively thin
diameter. In other words, a fuel vapor dissipation preventing
effect of the communication pipe 103 is small, and therefore, an
amount of dissipation of the fuel vapor toward the side of the
second canister 102 is large.
This can be improved by setting the length of the communication
pipe 103 to be large. However, if the length of the communication
pipe 103 is large, the resistance against flow of air within the
communication pipe 103 increases to prevent smooth flow of air
within the communication pipe 103 when air within the fuel tank is
allowed to be released to the outside, for example, during filling
of fuel into the fuel tank.
Therefore, there is a need in the art for a fuel vapor processing
apparatus that can decrease the amount of dissipation of fuel vapor
from a first space into a second space and can minimize resistance
of flow of air when air flows between the first space and the
second space.
SUMMARY OF THE INVENTION
One aspect according to the present invention includes a fuel vapor
processing apparatus including a communication passage connecting
between a first space and a second space each containing an
adsorption material capable of adsorbing fuel vapor. The
communication passage includes a dissipation delaying space capable
of delaying dissipation or transmission of the fuel vapor between
the first and second spaces. The communication passage further
includes throttles positioned to oppose to each other across the
dissipation delaying space.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view, with a part broken away, of a fuel vapor
processing apparatus having a first canister and a second canister
according to an embodiment of the present invention;
FIG. 2 is a front view of a transverse partition plate of the first
canister;
FIG. 3 is a view, with a part broken away, of a fuel vapor
processing apparatus having a first canister and a second canister
according to an alternative embodiment of the present
invention;
FIG. 4 is a view, with a part broken away, of a fuel vapor
processing apparatus having a canister according to another
alternative embodiment of the present invention;
FIG. 5 is a perspective view of a transverse partition member of
the canister shown in FIG. 4;
FIG. 6 is a schematic diagram of a fuel vapor processing apparatus
according to a further alternative embodiment of the present
invention;
FIG. 7(A) and FIG. 7(B) are front views of alternative partition
plates;
FIG. 8 is a schematic diagram of a fuel vapor processing apparatus
according to a further alternative embodiment of the present
invention; and
FIG. 9 is a schematic view of a known fuel vapor processing
apparatus.
DETAILED DESCRIPTION OF THE INVENTION
Each of the additional features and teachings disclosed above and
below may be utilized separately or in conjunction with other
features and teachings to provide improved fuel vapor processing
apparatus. Representative examples of the present invention, which
examples utilize many of these additional features and teachings
both separately and in conjunction with one another, will now be
described in detail with reference to the attached drawings. This
detailed description is merely intended to teach a person of skill
in the art further details for practicing preferred aspects of the
present teachings and is not intended to limit the scope of the
invention. Only the claims define the scope of the claimed
invention. Therefore, combinations of features and steps disclosed
in the following detailed description may not be necessary to
practice the invention in the broadest sense, and are instead
taught merely to particularly describe representative examples of
the invention. Moreover, various features of the representative
examples and the dependent claims may be combined in ways that are
not specifically enumerated in order to provide additional useful
embodiments of the present teachings.
In one embodiment, a fuel vapor processing apparatus includes a
first space and a second space. The first space communicates with a
space within a fuel tank and contains a tank-side adsorption
material therein, so that fuel vapor dissipating from the space
within the fuel tank can be adsorbed by the tank-side adsorption
material. The second space has a first end communicating with the
first space via a communication passage and has a second end open
into an atmosphere. The second space contains therein an
atmosphere-side adsorption material, so that a part of the fuel
vapor leaking from the first space can be adsorbed by the
atmosphere-side adsorption material. The communication passage
includes a dissipation delaying space and throttles. The
dissipation delaying space is capable of delaying dissipation of
the fuel vapor. The throttles are disposed on opposite sides of the
dissipation delaying space and are opposed to each other across the
dissipation delaying space.
Therefore, the fuel vapor dissipating from the first space into the
second space via the communication passage can be accumulated
within the communication passage, so that dissipation of the fuel
vapor into the second space can be inhibited. In other words, an
amount of the fuel vapor dissipating toward the side of the second
space can be reduced.
In addition, because the throttles are positioned to oppose to each
other across the dissipation delaying space, it is possible to
reduce resistance against flow of air through the communication
passage.
The fuel vapor processing apparatus may include a first canister
defining the first space therein and a second canister defining the
second space therein. The dissipation delaying space may be defined
within at least one of the first and second canisters or between
the first and second canisters.
In another embodiment, the fuel vapor processing apparatus includes
a single canister having the first space, the second space and the
dissipation delaying space defined therein.
The throttles may be positioned on the upper side of the
dissipation delaying space. With this arrangement, the fuel vapor
heavier than air can be effectively accumulated within the
dissipation delaying space, so that it is possible to further
decrease the amount of dissipation of the fuel vapor toward the
side of the second space.
An embodiment of the present invention will now be described with
reference to FIGS. 1 to 8. A fuel vapor processing apparatus
according to the embodiment is adapted to be mounted to a vehicle,
such as an automobile. In FIGS. 1 to 8, a front side, a rear side,
a left side, a right side, an upper side and a lower side
correspond to a front side, a rear side, a left side, a right side,
an upper side and a lower side of the fuel vapor processing
apparatus, respectively.
A fuel vapor processing apparatus 10 shown in FIG. 1 is aimed to
prevent fuel vapor produced within a fuel tank from leaking to the
atmosphere. As shown in FIG. 1, the apparatus 10 generally includes
a first canister 20 and a second canister 40 connected in series
with each other by a communication pipe 18.
<First Canister>
The first canister 20 has an adsorption material C contained
therein. The adsorption material C can adsorb and capture fuel
vapor that may be introduced into the first canister 20 from a
space within the fuel tank. As shown in FIG. 1, the first canister
20 includes a case body 21 and a cover 22. The case body 21 has an
internal space divided into a plurality of chambers. The cover 22
can close a rear opening (lower opening in FIG. 1) of the case body
21. More specifically, the internal space of the case body 21 is
divided into a main chamber 24 and an auxiliary chamber 25
separated by a longitudinal partition wall 21w that extends in
forward and rearward directions. The auxiliary chamber 25 is
divided further into a first auxiliary chamber 25a and a second
auxiliary chamber 25b by a transverse partition wall 23.
The adsorption material C is in forms of granules or particles and
is filled within the main chamber 24. The main chamber 24
communicates with a tank port 241 and a purge port 242 formed in a
front wall of the case body 21 via a perforated plate (not shown)
serving to hold the adsorption material C. The tank port 241 is
connected to the fuel tank via a fuel vapor passage (not shown).
The purge port 242 is connected to an intake air passage of an
internal combustion engine (not shown) via a purge passage (not
shown).
An internal cover plate 27 covers an opening of the main chamber 24
of the case body 21 formed on the side of the cover 22. The
internal cover plate 27 is configured to allow passage of gas and
includes a first filter 27f and a perforated plate 27x for holding
the adsorption material C within the main chamber 24.
The adsorption material C is also filled within the first auxiliary
chamber 25a of the auxiliary chamber 25 and is held by a second
filter 23f positioned on the side of the transverse partition plate
23. A rear opening of the first auxiliary chamber 25a is covered by
an internal cover plate 28 that includes a third filter 28f and a
perforated plate 28x. A space 26 is defined by the internal cover
plate 28 covering the first auxiliary chamber 25a, the internal
cover plate 27 covering the main chamber 24, and the cover 22 of
the case body 21. The space 26 serves as a communication space for
communicating between the main chamber 24 and the first auxiliary
chamber 25a.
The second auxiliary chamber 25b of the auxiliary chamber 25 serves
as a dissipation delaying chamber for delaying dissipation of the
fuel vapor that may be leaked from the first auxiliary chamber 25a.
The second auxiliary chamber 25b communicates with a connection
port 251 formed on a front wall of the case body 21. More
specifically, the connection port 251 is in communication with the
upper portion of the second auxiliary chamber 25b and is throttled
or narrowed in comparison with the upper portion of the second
auxiliary chamber 15b. The communication pipe 18 communicating with
the second canister 40 is connected to the connection port 251.
The transverse partition plate 23 dividing the auxiliary chamber 25
has through holes 234 serving as a throttle provided between the
first auxiliary chamber 25a and the second auxiliary chamber 25b.
As shown in FIG. 2, the transverse partition plate 23 has a
substantially rectangular plate body 232 having the though holes
234. The through holes 234, in this example, are three in number
and are arranged in right and left directions at the upper portion
of the plate body 232. A peripheral fixing portion 231 is formed at
the peripheral portion of the plate body 232 for fixing the plate
body 232 to the inner wall surface of the case body 21. A plurality
of projections 235 for holding the second filter 23f are formed on
the surface of the plate body 232 on the side of the first
auxiliary chamber 25a.
The three through holes 234 formed at the upper portion of the
plate body 232 are each configured to have a rectangular
window-like shape and are opposed to the connection port 251 across
the dissipation delaying space defined within the first auxiliary
chamber 25a. Because the three through holes 234 are formed at the
upper portion of the plate body 232 and the connecting port 251 is
in communication with the upper portion of the second auxiliary
chamber 25b, fuel vapor (heavier than air) leaked from the first
auxiliary chamber 25a via the through holes 234 may accumulate
within the lower portion of the second auxiliary chamber 25b that
serves as the dissipation delaying space.
The second canister 40 has a honeycomb adsorption material H
contained therein. The adsorption material H can adsorb and capture
fuel vapor that may be leaked from the first canister 20 and
introduced into the second canister 40 via the communication pipe
18. The second canister 40 includes a tubular case body 40m
containing the adsorption material H therein. A connection port 43
is formed at the front end of the case body 40m for connecting to
the communication pipe 18. In addition, an atmospheric port 45
opening into the atmosphere is formed at the rear end of the case
body 40m.
Each of the granular adsorption material C and the honeycomb
adsorption material H may be made of activated carbon or the like,
which can adsorb dissipating fuel vapor and can desorb the adsorbed
fuel by purging with air.
When fuel vapor is produced within the fuel tank during stopping of
the engine, the fuel vapor is introduced into the main chamber 24
of the first canister 20 via the fuel vapor passage and the tank
port 241 and is then adsorbed by the adsorption material C
contained in the main chamber 24. If a part of the fuel vapor
passes through the main chamber 24 to reach the first auxiliary
chamber 25a via the communication space 26, this part of the fuel
vapor can be adsorbed by the adsorption material C contained in the
first auxiliary chamber 25a. If this part of the fuel vapor cannot
be completely adsorbed by the adsorption material C contained in
the first auxiliary chamber 25a, the remaining fuel vapor can be
introduced into the second auxiliary chamber 25b (i.e., the
dissipation delaying chamber) via the through holes 234 of the
transverse partition plate 23 and can be accumulated within the
lower portion of the second auxiliary chamber 25b. If a part of the
fuel vapor accumulated within the second auxiliary chamber 25b
leaks from the second auxiliary chamber 25b, such a part of the
fuel vapor may be introduced into the second canister 40 via the
communication pipe 18 and can then be adsorbed by the honeycomb
adsorption material H.
On the other hand, if air is discharged from the fuel tank, for
example, during filling of fuel into the fuel tank, such air is
subsequently discharged to the outside via the fuel vapor passage,
the first canister 30, the communication pipe 18 and the second
canister 40.
During the operation of the engine, a negative pressure may be
produced within the intake air passage of the engine. Therefore,
outside air may flow into the second canister 40 via the
atmospheric port 45 and subsequently into the first canister 20 via
the communication pipe 18. After entering the first canister 20,
the air may flow through the second auxiliary chamber 25b, the
first auxiliary chamber 25a, the communication space 26 and the
main chamber 24 and may eventually flow into the intake air passage
of the engine via the purge port 242 and the purge passage. In this
occasion, no substantial resistance may be produced against flow of
the air, because the connection port 251 and the through holes 234
of the transverse partition plate 23 are opposed to each other
across the second auxiliary chamber 25b serving as the dissipation
delaying space.
Because the air flows from the second canister 40 into the first
canister 20 in this way, the fuel adsorbed by the honeycomb
adsorption material H and the granular adsorption materials C can
be purged with the air and desorbed from the adsorption materials H
and C. The fuel desorbed from the adsorption materials H and C can
be therefore carried by the air and can be supplied into the intake
air passage of the engine.
With the above arrangement, the fuel vapor processing apparatus 10
of this embodiment can effectively prevent fuel vapor produced into
the fuel tank from flowing into the atmosphere.
In the above embodiment, the main chamber 24, the communication
space 26 and the first auxiliary chamber 25a of the first canister
20 serve as a first space. The second auxiliary chamber 25b and the
communication pipe 18 serve as a communication passage. The second
auxiliary chamber 25b serves as the dissipation delaying space. The
internal space of the second canister 40 serves as a second space.
The through holes 234 of the transverse partition plate 23 of the
first canister 20 and the connection port 251 serve as throttles.
The adsorption materials C serve as a tank-side adsorption
material. The adsorption material H serves as an atmosphere-side
adsorption material.
According to the fuel vapor processing apparatus 10 of this
embodiment, the communication passage communicating between the
main chamber 24, the communication space 26 and the first auxiliary
chamber 25a (serving as the first space) of the first canister 20
and the internal space (serving as the second space) of the second
canister 40 includes the dissipation delaying space (second
auxiliary chamber 25b) for delaying dissipation of the fuel vapor
and the throttles (the through holes 234 of the transverse
partition plate 23 and the connecting port 251) provided on
opposite sides of the dissipation delaying space. Therefore, it is
possible to inhibit or minimize potential dissipation of the fuel
vapor from the first auxiliary chamber 25a (i.e., the first space)
into the second canister 40 via the second auxiliary chamber 25b
(i.e., the dissipation delaying space) and the communication pipe
18, because the fuel vapor may be accumulated within the second
auxiliary chamber 25b (i.e., the dissipation delaying space). In
other words, it is possible to reduce the amount of dissipation of
fuel vapor toward the side of the second canister 40.
In addition, because the second auxiliary chamber 25b (i.e., the
dissipation delaying space) is provided between the through holes
234 of the transverse partition plate 23 and the connection port
251 (i.e., the throttles) which are opposed to each other, it is
possible to prevent increase of resistance against flow of air
through the second auxiliary chamber 25b (i.e., the dissipation
delaying space) during filling of fuel into the fuel tank or during
the operation of the engine.
Further, because the through holes 234 of the transverse partition
plate 23 and the connection port 251 provided on opposite sides
with respect to the second auxiliary chamber 25b (i.e., the
dissipation delaying space) are positioned on the upper side of the
second auxiliary chamber 25b, the fuel vapor heavier than air can
be effectively accumulated within the second auxiliary chamber 25b
(i.e., the dissipation delaying space). Therefore, it is possible
to reduce the amount of dissipation of the fuel vapor toward the
side of the second canister 40.
The present invention may not be limited to the above embodiment
may be modified in various ways within the scope of the invention.
FIGS. 3 to 8 show various alternative embodiments. In these figures
like members are given the same reference numbers as the first
embodiment and description of these members will not be
repeated.
In the above embodiment, the second auxiliary chamber 25b
(dissipation delaying space) is provided within the first canister
20, and the through holes 234 of the transverse partition plate 23
and the connection port 251 are used as the throttles. However, as
shown in FIG. 3, it is possible to provide the transverse partition
plate 23 within the second canister 40, so that a space 41 between
the transverse partition plate 23 and the connection port 43 can be
used as a dissipation delaying space. In this case, the
configuration of the transverse partition plate 23 may be suitably
changed to correspond to the cross sectional shape of the second
canister 40.
In addition, although the fuel vapor processing apparatus 10 of the
above embodiment has the first canister 20 and the second canister
40 that are formed separately from each other, the first and second
canisters 20 and 40 can be integrated into a single canister 120 as
shown in FIG. 4. The internal space of the case body 21 of the
canister 120 is divided into the main chamber 24 and the auxiliary
chamber 25 by the longitudinal partition wall 21w. The auxiliary
chamber 25 is further divided into the first auxiliary chamber 25a,
the second auxiliary chamber 25b and a third auxiliary chamber 25c
by a transverse partition member 60. Each of the first auxiliary
chamber 25a and the third auxiliary chamber 25c has the adsorption
material C contained therein. The second auxiliary chamber 25b is
positioned between the first auxiliary chamber 25a and the third
auxiliary chamber 25c, which are positioned on the rear side and
the front side of the second auxiliary chamber 25b, respectively.
In this embodiment, the second auxiliary chamber 25b serves as a
dissipation delaying space. The atmospheric port 45 is formed at
the front wall of the case body 21 and communicates with the third
auxiliary chamber 15c via a filter 45f.
As shown in FIG. 5, the transverse partition member 60 includes a
pair of front and rear transverse partition plates 62 and a
connection plate 63 connecting the transverse partition plates 62
to each other, so that the transverse partition plates 62 are held
in parallel to each other. In this example, four window-like
through holes 62h are formed in the upper portion of each of the
transverse partition plates 62 and are arranged in the right and
left directions, so that the through holes 62h of the front
transverse partition plate 62 and the through holes 62h of the rear
transverse partition plate 62 are opposed to each other across the
dissipation delaying space. The peripheral portions of the
transverse partition plates 62 can be fixed to the inner wall of
the case body 21, for example, by bonding or other suitable means.
Projections 62t are formed on the surface of the transverse
partition plate 62 on the side of the first auxiliary chamber 25a
and also on the surface of the transverse partition plate 62 on the
side of the third auxiliary chamber 25c for holding filters 62f and
62e against these surfaces, respectively.
Thus, according to the canister 120 of this alternative embodiment,
the main chamber 24, the communication space 26 and the first
auxiliary chamber 25a serve as a first space, the second auxiliary
chamber 25b serves as the dissipation delaying space, and the third
auxiliary chamber 25c serves as a second space. The through holes
62h on opposite sides of the transverse partition member 60 serve
as throttles. The adsorption materials C contained in the main
chamber 24 and the first auxiliary chamber 25a serve as a tank-side
adsorption material. The adsorption material C contained in the
third auxiliary chamber 25c serves as an atmosphere-side adsorption
material.
Further, although the dissipation delaying space is formed within
the first canister 20, the second canister 20 or the canister 120
in the above embodiments, it is possible to provide a container 70
defining a dissipation delaying space therein and connected to the
first canister 20 and the second canister 50 via respective
connecting passages 72. In this case, ports of the container 70 for
connecting to the connecting passages 72 may serve as
throttles.
Furthermore, although the through holes 234 and the through holes
62h are formed to be arranged in the right and left directions in
the upper portions of the transverse partition plate 23 and the
transverse partition plates 62, respectively, in the above
embodiments, the through holes 234 (62h) can also be formed in
series into a single elongated hole as shown in FIG. 7(A) or 7(B).
In addition, the configuration of the transverse partition plate 23
and the configurations of the transverse partition plates 62 can be
suitably changed as shown in FIGS. 7(A) and 7(B).
Furthermore, although the dissipation delaying space is formed
within the first canister 20, the second canister 20 or the single
canister 120 in the above embodiments, it is possible to provide
the dissipation delaying spaces 25b and 41 within the first
canister 20 and the second canister 40, respectively, as shown in
FIG. 8.
Furthermore, although the honeycomb adsorption material H is used
as an adsorption material of the second canister 40, the granular
adsorption material C can be used in place of the honeycomb
adsorption material H.
* * * * *